I used R18S3+MTG cryopreservation media to store sperms, obtained from the cauda epididymis of male mice. After one week, I thawed the sperm from liquid nitrogen, using a 37 C water bath. I checked them under dissecting microscope but it seems they are all stationary with a very few of motile. Those that are even motile cannot move as fast as they used to be before storing in the liquid nitrogen. is it normal to see the sperm less motile and less active after freeze and thaw? and can that be used for in vitro fertilization?